Viewer window

Click and drag in the window to tumble the model. Use the mouse wheel to zoom in and out.


  • Load...
      Load a saved .vvc file
  • Save...
      Save current layout as a .vvc file.
  • Save Snapshot...
      Save current view as a PNG file.


  • Select any of these to load demo configurations that demonstrate interesting aspects of the viewer.


Data Source

Data Source
Data Source
  • URL

      A path to a .zip file containing image volume data. The viewer reads images in the order they are encountered in the zip file. Images can be in TIF, PNG, GIF, JPG or PNM format.

      If you decide to upload your own data, be careful not to exceede the memory limits of the application (currently set to a maximum of 1GB). The demo datasets fit within a 256x256x128 volume.

  • Presets
      Load one of the demo datasets directly from the server. Helpful for testing.


  • Width

      Relative width of displayed volume.

  • Height

      Relative height of displayed volume.

  • Depth

      Relative depth of displayed volume.

  • Show bounds

      Draw bounding box around entire volume.

  • Show lightbuffer

      When drawing with diffuse light, show the calculated shadow in the upper right hand corner. This is the model seen from the light's point of view.

  • Multisample

      By default, the program will calculate only one color value per pixel. By enabling multisampling, it will calculate 8 slightly different values per pixel and blend them together. This can smooth jagged edges and provide better looking images.

  • Slices

      Number of slices through the data to draw. Larger values make for more detailed renderings. Smaller values make the program more responsive.

  • Opacity

      Adjust the opacity for all pixels in the model. For best viewing, this should be set to about the same value as Slices.

      This isn't a simple multiplier for all density information - instead, it provide a correction factor so that when you adjust the number of slices the total overall opacity of the model does not seem to change.


  • Front/Back

      Click and drag to change light direction.

  • Color

      Light color

  • Type
    • None - Draw the transfer color with opacity.
    • Phong - Use light direction to add a shine to parts of the model facing that direction.
    • Diffuse - Use the calculated shadow buffer to add extra shading information to the rendering.


Paint Transfer Function
  • Histogram

      Draw histogram data underneath the painting area.

      The histogram provides information about how the volume data is laid out. The horizontal axis represents the density of the volume data. The vertical axis represents how likely it is a piece of the model represents an edge (aka: the local change in density in math speak). Pixel brightness indicates what percentage of the source data maps to this particular density/edginess coordinate.

  • Display opacity

      How much of the histogram is obscured by the transfer function overlay. This does not affect the rendering - it just makes painting the transfer function easier.

    • Color - Draw using color
    • Mask - Draw into the opacity of the transfer function instead of the color. This makes it easy to erase sections of the image without affecting the color.
  • Brush
    • Brush
        Draw into the transfer function
    • Eraser
        Erase parts of the transfer function
    • Size
        Set the size of the brush
    • Sharp
        Set the sharpness of the brush
    • Opacity
        Set the opacity of the brush
    • Color
        Set the color of the brush

Clip Sectors

Clip Sectors
Clip Sectors
  • Center X/Y/Z

      Changes the dividing point for calculating the sectors. By default, all sectors are of equal size. By changing these values, you change the fraction of the volume a sector contains. For example, by setting Center X to .2, the -X sectors will only see 20% of the model while the +X sectors will see the remaining 80%.

  • Check Boxes

      If checked, indicates the coresponding sector is visible.

  • Speed buttons

      Provides a fast way to select common combinations of sectors.